Can biotin make your nails worse? You won’t make your nails grow more quickly if you take this dietary supplement. But several studies show that biotin can strengthen brittle nails, making them less likely to split or break, so you may be able to grow your nails longer after taking the supplement regularly.
How long does biotin take to work on nails? six to 12 months
What are the symptoms of too much biotin? Biotin supplements can cause problems if you take too much. Side effects can include skin rashes, digestive upset, problems with insulin release, and kidney problems. As with any supplement, the safety of long-term or high-dose use isn’t known.